1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
|
/* $Id: entry.S,v 1.37 2004/06/11 13:02:46 doyu Exp $
*
* linux/arch/sh/entry.S
*
* Copyright (C) 1999, 2000, 2002 Niibe Yutaka
* Copyright (C) 2003 Paul Mundt
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
*/
! NOTE:
! GNU as (as of 2.9.1) changes bf/s into bt/s and bra, when the address
! to be jumped is too far, but it causes illegal slot exception.
/*
* entry.S contains the system-call and fault low-level handling routines.
* This also contains the timer-interrupt handler, as well as all interrupts
* and faults that can result in a task-switch.
*
* NOTE: This code handles signal-recognition, which happens every time
* after a timer-interrupt and after each system call.
*
* NOTE: This code uses a convention that instructions in the delay slot
* of a transfer-control instruction are indented by an extra space, thus:
*
* jmp @k0 ! control-transfer instruction
* ldc k1, ssr ! delay slot
*
* Stack layout in 'ret_from_syscall':
* ptrace needs to have all regs on the stack.
* if the order here is changed, it needs to be
* updated in ptrace.c and ptrace.h
*
* r0
* ...
* r15 = stack pointer
* spc
* pr
* ssr
* gbr
* mach
* macl
* syscall #
*
*/
#if defined(CONFIG_PREEMPT)
# define preempt_stop() cli
#else
# define preempt_stop()
# define resume_kernel __restore_all
#endif
#if defined(CONFIG_SH_STANDARD_BIOS) || defined(CONFIG_SH_KGDB)
! Handle kernel debug if either kgdb (SW) or gdb-stub (FW) is present.
! If both are configured, handle the debug traps (breakpoints) in SW,
! but still allow BIOS traps to FW.
.align 2
debug_kernel:
#if defined(CONFIG_SH_STANDARD_BIOS) && defined(CONFIG_SH_KGDB)
/* Force BIOS call to FW (debug_trap put TRA in r8) */
mov r8,r0
shlr2 r0
cmp/eq #0x3f,r0
bt debug_kernel_fw
#endif /* CONFIG_SH_STANDARD_BIOS && CONFIG_SH_KGDB */
debug_enter:
#if defined(CONFIG_SH_KGDB)
/* Jump to kgdb, pass stacked regs as arg */
debug_kernel_sw:
mov.l 3f, r0
jmp @r0
mov r15, r4
.align 2
3: .long kgdb_handle_exception
#endif /* CONFIG_SH_KGDB */
#endif /* CONFIG_SH_STANDARD_BIOS || CONFIG_SH_KGDB */
.align 2
debug_trap:
#if defined(CONFIG_SH_STANDARD_BIOS) || defined(CONFIG_SH_KGDB)
mov #OFF_SR, r0
mov.l @(r0,r15), r0 ! get status register
shll r0
shll r0 ! kernel space?
bt/s debug_kernel
#endif
mov.l @r15, r0 ! Restore R0 value
mov.l 1f, r8
jmp @r8
nop
.align 2
ENTRY(exception_error)
!
#ifdef CONFIG_TRACE_IRQFLAGS
mov.l 3f, r0
jsr @r0
nop
#endif
sti
mov.l 2f, r0
jmp @r0
nop
!
.align 2
1: .long break_point_trap_software
2: .long do_exception_error
#ifdef CONFIG_TRACE_IRQFLAGS
3: .long trace_hardirqs_on
#endif
.align 2
ret_from_exception:
preempt_stop()
#ifdef CONFIG_TRACE_IRQFLAGS
mov.l 4f, r0
jsr @r0
nop
#endif
ENTRY(ret_from_irq)
!
mov #OFF_SR, r0
mov.l @(r0,r15), r0 ! get status register
shll r0
shll r0 ! kernel space?
get_current_thread_info r8, r0
bt resume_kernel ! Yes, it's from kernel, go back soon
#ifdef CONFIG_PREEMPT
bra resume_userspace
nop
ENTRY(resume_kernel)
mov.l @(TI_PRE_COUNT,r8), r0 ! current_thread_info->preempt_count
tst r0, r0
bf noresched
need_resched:
mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags
tst #_TIF_NEED_RESCHED, r0 ! need_resched set?
bt noresched
mov #OFF_SR, r0
mov.l @(r0,r15), r0 ! get status register
and #0xf0, r0 ! interrupts off (exception path)?
cmp/eq #0xf0, r0
bt noresched
mov.l 1f, r0
mov.l r0, @(TI_PRE_COUNT,r8)
#ifdef CONFIG_TRACE_IRQFLAGS
mov.l 3f, r0
jsr @r0
nop
#endif
sti
mov.l 2f, r0
jsr @r0
nop
mov #0, r0
mov.l r0, @(TI_PRE_COUNT,r8)
cli
#ifdef CONFIG_TRACE_IRQFLAGS
mov.l 4f, r0
jsr @r0
nop
#endif
bra need_resched
nop
noresched:
bra __restore_all
nop
.align 2
1: .long PREEMPT_ACTIVE
2: .long schedule
#ifdef CONFIG_TRACE_IRQFLAGS
3: .long trace_hardirqs_on
4: .long trace_hardirqs_off
#endif
#endif
ENTRY(resume_userspace)
! r8: current_thread_info
cli
#ifdef CONFIG_TRACE_IRQFLAGS
mov.l 5f, r0
jsr @r0
nop
#endif
mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags
tst #_TIF_WORK_MASK, r0
bt/s __restore_all
tst #_TIF_NEED_RESCHED, r0
.align 2
work_pending:
! r0: current_thread_info->flags
! r8: current_thread_info
! t: result of "tst #_TIF_NEED_RESCHED, r0"
bf/s work_resched
tst #(_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK), r0
work_notifysig:
bt/s __restore_all
mov r15, r4
mov r12, r5 ! set arg1(save_r0)
mov r0, r6
mov.l 2f, r1
mov.l 3f, r0
jmp @r1
lds r0, pr
work_resched:
#ifndef CONFIG_PREEMPT
! gUSA handling
mov.l @(OFF_SP,r15), r0 ! get user space stack pointer
mov r0, r1
shll r0
bf/s 1f
shll r0
bf/s 1f
mov #OFF_PC, r0
! SP >= 0xc0000000 : gUSA mark
mov.l @(r0,r15), r2 ! get user space PC (program counter)
mov.l @(OFF_R0,r15), r3 ! end point
cmp/hs r3, r2 ! r2 >= r3?
bt 1f
add r3, r1 ! rewind point #2
mov.l r1, @(r0,r15) ! reset PC to rewind point #2
!
1:
#endif
mov.l 1f, r1
jsr @r1 ! schedule
nop
cli
#ifdef CONFIG_TRACE_IRQFLAGS
mov.l 5f, r0
jsr @r0
nop
#endif
!
mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags
tst #_TIF_WORK_MASK, r0
bt __restore_all
bra work_pending
tst #_TIF_NEED_RESCHED, r0
.align 2
1: .long schedule
2: .long do_notify_resume
3: .long restore_all
#ifdef CONFIG_TRACE_IRQFLAGS
4: .long trace_hardirqs_on
5: .long trace_hardirqs_off
#endif
.align 2
syscall_exit_work:
! r0: current_thread_info->flags
! r8: current_thread_info
tst #_TIF_SYSCALL_TRACE, r0
bt/s work_pending
tst #_TIF_NEED_RESCHED, r0
#ifdef CONFIG_TRACE_IRQFLAGS
mov.l 5f, r0
jsr @r0
nop
#endif
sti
! XXX setup arguments...
mov.l 4f, r0 ! do_syscall_trace
jsr @r0
nop
bra resume_userspace
nop
.align 2
syscall_trace_entry:
! Yes it is traced.
! XXX setup arguments...
mov.l 4f, r11 ! Call do_syscall_trace which notifies
jsr @r11 ! superior (will chomp R[0-7])
nop
! Reload R0-R4 from kernel stack, where the
! parent may have modified them using
! ptrace(POKEUSR). (Note that R0-R2 are
! used by the system call handler directly
! from the kernel stack anyway, so don't need
! to be reloaded here.) This allows the parent
! to rewrite system calls and args on the fly.
mov.l @(OFF_R4,r15), r4 ! arg0
mov.l @(OFF_R5,r15), r5
mov.l @(OFF_R6,r15), r6
mov.l @(OFF_R7,r15), r7 ! arg3
mov.l @(OFF_R3,r15), r3 ! syscall_nr
!
mov.l 2f, r10 ! Number of syscalls
cmp/hs r10, r3
bf syscall_call
mov #-ENOSYS, r0
bra syscall_exit
mov.l r0, @(OFF_R0,r15) ! Return value
__restore_all:
mov.l 1f, r0
jmp @r0
nop
.align 2
1: .long restore_all
.align 2
not_syscall_tra:
bra debug_trap
nop
.align 2
syscall_badsys: ! Bad syscall number
mov #-ENOSYS, r0
bra resume_userspace
mov.l r0, @(OFF_R0,r15) ! Return value
/*
* Syscall interface:
*
* Syscall #: R3
* Arguments #0 to #3: R4--R7
* Arguments #4 to #6: R0, R1, R2
* TRA: (number of arguments + 0x10) x 4
*
* This code also handles delegating other traps to the BIOS/gdb stub
* according to:
*
* Trap number
* (TRA>>2) Purpose
* -------- -------
* 0x0-0xf old syscall ABI
* 0x10-0x1f new syscall ABI
* 0x20-0xff delegated through debug_trap to BIOS/gdb stub.
*
* Note: When we're first called, the TRA value must be shifted
* right 2 bits in order to get the value that was used as the "trapa"
* argument.
*/
.align 2
.globl ret_from_fork
ret_from_fork:
mov.l 1f, r8
jsr @r8
mov r0, r4
bra syscall_exit
nop
.align 2
1: .long schedule_tail
!
ENTRY(system_call)
#if !defined(CONFIG_CPU_SH2)
mov.l 1f, r9
mov.l @r9, r8 ! Read from TRA (Trap Address) Register
#endif
!
! Is the trap argument >= 0x20? (TRA will be >= 0x80)
mov #0x7f, r9
cmp/hi r9, r8
bt/s not_syscall_tra
mov #OFF_TRA, r9
add r15, r9
mov.l r8, @r9 ! set TRA value to tra
#ifdef CONFIG_TRACE_IRQFLAGS
mov.l 5f, r10
jsr @r10
nop
#endif
sti
!
get_current_thread_info r8, r10
mov.l @(TI_FLAGS,r8), r8
mov #_TIF_SYSCALL_TRACE, r10
tst r10, r8
bf syscall_trace_entry
!
mov.l 2f, r8 ! Number of syscalls
cmp/hs r8, r3
bt syscall_badsys
!
syscall_call:
shll2 r3 ! x4
mov.l 3f, r8 ! Load the address of sys_call_table
add r8, r3
mov.l @r3, r8
jsr @r8 ! jump to specific syscall handler
nop
mov.l @(OFF_R0,r15), r12 ! save r0
mov.l r0, @(OFF_R0,r15) ! save the return value
!
syscall_exit:
cli
#ifdef CONFIG_TRACE_IRQFLAGS
mov.l 6f, r0
jsr @r0
nop
#endif
!
get_current_thread_info r8, r0
mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags
tst #_TIF_ALLWORK_MASK, r0
bf syscall_exit_work
bra __restore_all
nop
.align 2
#if !defined(CONFIG_CPU_SH2)
1: .long TRA
#endif
2: .long NR_syscalls
3: .long sys_call_table
4: .long do_syscall_trace
#ifdef CONFIG_TRACE_IRQFLAGS
5: .long trace_hardirqs_on
6: .long trace_hardirqs_off
#endif
|
